Question: Solve for $x$ and $y$ using substitution. ${2x-4y = -6}$ ${x = 5y-6}$
Answer: Since $x$ has already been solved for, substitute $5y-6$ for $x$ in the first equation. ${2}{(5y-6)}{- 4y = -6}$ Simplify and solve for $y$ $10y-12 - 4y = -6$ $6y-12 = -6$ $6y-12{+12} = -6{+12}$ $6y = 6$ $\dfrac{6y}{{6}} = \dfrac{6}{{6}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = 5y-6}\thinspace$ to find $x$ ${x = 5}{(1)}{ - 6}$ $x = 5 - 6$ ${x = -1}$ You can also plug ${y = 1}$ into $\thinspace {2x-4y = -6}\thinspace$ and get the same answer for $x$ : ${2x - 4}{(1)}{= -6}$ ${x = -1}$